Does anybody know about wu, ye, and yi? There seems to be only a Japanese page on the ye character on wikipedia. The rest only have korean pages. I know these are not used anymore but they seem very interesting because it makes me wonder why people have stopped using these characters or when they have used them.

You are talking about わゐうゑを, right?
Honestly, I know next to nothing about them. But I knew a few aged people who actually used them even in 1990s.
In terms of the history, this wikipedia page "歴史的仮名遣" explains it quite precisely though, unfortunately, it doesn't seem very easy to summarize it.

NileCat wrote:You are talking about わゐうゑを, right?
Honestly, I know next to nothing about them. But I knew a few aged people who actually used them even in 1990s.
In terms of the history, this wikipedia page "歴史的仮名遣" explains it quite precisely though, unfortunately, it doesn't seem very easy to summarize it.

While my time in Japan was between 1987-1999, I remember that I was told these characters were not in use. I think the only places I ever saw these characters/kana was in an old King James (japanese) Bible and a few chirashi (pamphlets) that we had. I did learn them in the beginning but soon ignored them as I can count the times I've seen them over 20 years on both hands..

two_heads_talking wrote:While my time in Japan was between 1987-1999, I remember that I was told these characters were not in use.

Yeah, that's true.
But as the wikipedia says, the archaic kana was officially used before the WWII ended. Some old people who spent their youth before the war (born in around 1910-20) sometimes couldn't stop using those archaic characters especially when they got very old. As you know, human memory's work can be strange at times. I remember one of my relatives often used ゐ and ゑ, and something like けふ（きょう） or てふてふ（ちょうちょう） in his mails or 年賀状. I was interested in that when I was a child.
That's one of my personal experiences.

two_heads_talking wrote:While my time in Japan was between 1987-1999, I remember that I was told these characters were not in use.

Yeah, that's true.
But as the wikipedia says, the archaic kana was officially used before the WWII ended. Some old people who spent their youth before the war (born in around 1910-20) sometimes couldn't stop using those archaic characters especially when they got very old. As you know, human memory's work can be strange at times. I remember one of my relatives often used ゐ and ゑ, and something like けふ（きょう） or てふてふ（ちょうちょう） in his mails or 年賀状. I was interested in that when I was a child.
That's one of my personal experiences.

You are absolutely correct. I did run into the kana a few times, myself. But unless one is focusing on pre/post WWII, one probably won't see them very often, if at all.

I'm interested too. It would be nice if there were corresponding pages on Japanese wikipedia for those characters, although I assume there must be a logical reason for not having them, if they are not already there. At the same time, I can't imagine what that would be. I'll search around and see if I can find anything.

The 江 derived character (pronounced ye but looking similar to い) is a hentaigana and yet there are other characters defined as hentaigana which do not have their own article. I'll try and investigate that too.

EDIT: (To avoid double-posting)

they seem very interesting because it makes me wonder why people have stopped using these characters

This is only a small part of your original post and doesn't fully answer this question either, but probably has large relevance.

(from 'ya-gyou-e' article)「現在その位置(the location of the old character on the hiragana chart)は空白にするかア行エの繰り返しで埋められるが、本来は別の仮名と音があった。」

So it is literally the disappearance of the sound itself that has caused the loss of (some of) these characters. Why did the sounds disappear? I believe this is because it was easier to pronounce the sound another way, as we commonly come across such cases in English. Therefore the character started to represent an already existing sound which had its own character, and therefore became redundant. Sorry if this was already clear to you.

Interesting.
I noticed there was a gap in perception between you and I.
Let me explain about the general perception among Japanese people. Since I'm not an expert, my opinion wouldn't be accurate in the academic definition, though.
First of all, please note that Japanese language didn't have letters before 4th century. The oldest Japanese book called 古事記 was written using only Chinese kanji characters, which were ideogram (表意文字) . Kana, which is phonogram (表音文字), was invented in around 7-8th century. It is known as 万葉仮名. They created the new character set using Chinese kanji. Do you know why it is called kana? The original kanji was called 真名 (mana), meaning "true character". They named the new Japanese original character 仮名 (kana), meaning "provisional character". According to wikipedia, they had 973 characters at that time!! Katakana (片仮名) was invented a century later than that in order to annotate Chinese texts. In a way, hiragana was a simplified version of kanji, and katakana was a simplified version of hiragana.
Thus, in our history, evolution of written characters are the history of simplification. Many letters (characters) were lost in the course of the evolution. And the sounds (pronunciation) as well. Hentaigana was also in this stream of the history. I mean, you can't divide 片仮名 and 平仮名 in the historical context. Because they are both 仮名. They only named the different (archaic) 仮名 characters as hentaigana (変体仮名) in 20th century.

Ongakuka wrote:The 江 derived character (pronounced ye but looking similar to い) is a hentaigana and yet there are other characters defined as hentaigana which do not have their own article. I'll try and investigate that too.

So, returning to the original question "why or how the sounds have been lost?", the wikipedia page 「上代特殊仮名遣」would provide you a rough answer. But I confess it's beyond my understanding... All I can do is to point out this particular sentence:
上代日本語は50音ではなく87音（あるいは88音）あった

This page http://ja.wikipedia.org/wiki/変体仮名 (someone teach me how to do links?) shows alternative forms of characters, some of which appear very occasionally for stylistic purposes, but what really interests me is that just one of them has its own article on wikipedia (ヤ行のエ). I'm not saying they should all have their own article, but why does that particlar hentaigana character have one? I guess someone just felt like contributing knowledge at random. Or this is a project just underway: I didn't check the date of the article. Anyway I suppose this does not solve the mystery of the 'yi' and or 'wu' characters.

Basically as Nilecat-san says, there is no kana for 'yi, ye and wu,' but there do exist 'fake' ones created in the Meiji era to represent sounds believed to be used in pre-classical Japanese. These quickly died out of fashion, it seems (probably because the sounds themselves weren't in use anyway.) Hope that helps.

Ongakuka; I fixed your link up there. It wasn't really wrong... it's just that when you copy/paste from the browser address bar, it usually changes the kana/kanji to be URL encoded to avoid messing up the link in other programs etc that might not correctly handle Japanese text.

Ongakuka wrote:This page http://ja.wikipedia.org/wiki/変体仮名 (someone teach me how to do links?) shows alternative forms of characters, some of which appear very occasionally for stylistic purposes, but what really interests me is that just one of them has its own article on wikipedia (ヤ行のエ). I'm not saying they should all have their own article, but why does that particlar hentaigana character have one? I guess someone just felt like contributing knowledge at random. Or this is a project just underway: I didn't check the date of the article.

That's because 江 is still used in some cases. （芸能人が色紙にサインするときなど、「～さん江」という「当て字」として使われます）
In addition to that, you could find the answer at the end of the page, I guess.
It says:

Thanks everyone for finding more about those characters! I think what you guys said made sense. Using Chinese characters to represent sounds means that writing takes longer since there are many strokes. It's reasonable that eventually another system was made to represent the same sounds, of which were also having less variety, in fewer and fewer characters to prevent redundancy and perhaps make it easier to write. It would make sense that these other characters existed considering the time kana was invented..